Before building an assembly, it is a good idea to have at least a sketch of the typical cross section of your design so that you have something to reference as you work. Having detailed dimensions is helpful but not critical—the subassemblies can be changed with relative ease, even after the corridor has been built.
To create an assembly that represents the cross section of a road, follow these steps:
- Open the drawing named Creating an Assembly.dwg located in the Chapter 09 class data folder.
- On the Home tab of the ribbon, click AssemblyCreate Assembly.
- In the Create Assembly dialog box, enter Subdivision Road as the name.
- For Code Set Style, select All Codes With Hatching. Click OK.
- Click a point near the center of the top right viewport to insert the assembly baseline. A vertical red line will appear in your drawing.
- On the Home tab of the ribbon, click the Tool Palettes icon.
- On the Tool Palettes window, right-click the gray strip labeled Tool Palettes and select Civil Imperial (Metric) Subassemblies.
- Click the stack of tabs at the bottom of the tool palette window, and then click Basic, as shown in Figure 9.6.
Figure 9.6 Selecting the Basic tool palette - On the Basic tool palette, click BasicLane. The Properties window will appear, and you will be prompted on the command line to select a marker point.
- In the Properties window, verify that Side is set to Right, and then click the marker at the midpoint of the assembly baseline. A lane subassembly is attached to the assembly baseline.
- On the Basic tool palette, click BasicCurbAndGutter.
- In the Properties window, change the value for Curb Height to 0.50 (0.15).
- Click the upper-right circle marker on the lane subassembly you inserted earlier. A subassembly representing curb and gutter is now attached to the lane.
Tips :You may need to zoom in to see the circle markers on the lane subassembly.
- Press Esc to end the assembly insertion command. Click the lane subassembly and the curb subassembly, and then click Mirror on the ribbon.
Tips :This is not the same Mirror command that AutoCAD® software uses for mirroring lines, arcs, and circles. This is a special command for subassemblies, and it must be used instead of the AutoCAD version.
- Click the vertical red assembly baseline. Both sides of the assembly now display a lane and curb subassembly.
What Are Subassemblies Made Of?
Subassemblies are made up of three fundamental components: points, links, and shapes. A point is self-explanatory, a link is a line that is drawn between two points, and a shape is the result of three or more links forming a closed shape, as shown in the following diagram. Each point, link, and shape in a subassembly has at least one code. These codes are used to identify the purpose of a component and control its style, behavior, and relationship to other parts of the design. A collection of styles that apply to multiple codes is called a code set style.
A Note about Units
Throughout this discuss, you'll notice that two values are provided for units of measurement. The first value is provided for the imperial system that is used in the United States, and the second value, in parentheses, is provided for the metric system that is used in many other countries. These values most often represent imperial feet and metric meters. It is important to note that, generally, only the numeric values are entered in the software, not terms like feet or meters. Also, you should know that the two numbers provided are not necessarily equal. In most cases, they are similar values that are rounded to work efficiently in their respective measurement systems.